EDP Sciences
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Volume 388, Number 3, June IV 2002
Page(s) 793 - 808
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20020539

A&A 388, 793-808 (2002)
DOI: 10.1051/0004-6361:20020539

Dark and luminous matter in the NGC 3992 group of galaxies

I. The large barred spiral NGC 3992
R. Bottema1 and M. A. W. Verheijen2

1  Kapteyn Astronomical Institute, PO Box 800, 9700 AV Groningen, The Netherlands
2  University of Wisconsin, Department of Astronomy, 475 North Charter Street, Madison, WI 53706, USA
    e-mail: verheyen@astro.wisc.edu

(Received 24 July 2001 / Accepted 8 April 2002 )

Detailed neutral hydrogen observations have been obtained of the large barred spiral galaxy NGC 3992 and its three small companion galaxies, UGC 6923, UGC 6940, and UGC 6969. For the main galaxy, the H I distribution is regular with a low level radial extension outside the stellar disc. However, at exactly the region of the bar, there is a pronounced central H I hole in the gas distribution. Likely gas has been transported inwards by the bar and because of the emptyness of the hole no large accretion events can have happened in recent galactic times. The gas kinematics is very regular and it is demonstrated that the influence of the bar potential on the velocity field is negligible. A precise and extended rotation curve has been derived showing some distinct features which can be explained by the non-exponential radial light distribution of NGC 3992. The decomposition of the rotation curve gives a slight preference for a sub maximal disc, though a range of disc contributions, up to a maximum disc situation fits nearly equally well. For such a maximum disc contribution, which might be expected in order to generate and maintain the bar, the required mass-to-light ratio is large but not exceptional.

Key words: galaxies: individual: NGC 3992 -- ISM: kinematics and dynamics -- galaxies: kinematics and dynamics  -- galaxies: spiral

Offprint request: R. Bottema, robot@astro.rug.nl

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